Question

The coordination number of platinum in \([\text{PtCl}(\text{C}_5\text{H}_5\text{N})(\text{NH}_3)]\) is-

• A. 3
• B. 4
• C. 5
• D. 6

Hint:

Coordination number depends on the number of donor atoms, not on the number of ligands or charges present.

Answer 1

The Correct Option is A

Step 1: Coordination number is defined as the number of ligand donor atoms directly bonded to the central metal atom.
Step 2: In the complex \([\text{PtCl}(\text{C}_5\text{H}_5\text{N})(\text{NH}_3)]\), the ligands present are: \begin{itemize} \item \(\text{Cl}^-\) : monodentate ligand (1 donor atom) \item \(\text{C}_5\text{H}_5\text{N}\) (pyridine): monodentate ligand (1 donor atom) \item \(\text{NH}_3\): monodentate ligand (1 donor atom) \end{itemize}
Step 3: Total number of donor atoms attached to platinum: \[ 1 + 1 + 1 = 3 \]
Step 4: Hence, the coordination number of platinum is 3.